REF-184 · Faiss et al., 2013/2015; Kasai et al., 2015/2017/2019 · PLoS One
RSH Research Cluster: Molecular mechanisms and practical applications of repeated-sprint training in hypoxia
Consolidated Review
This cluster consolidates original studies behind the RSH review REF-183. Only the first two have been checked against their abstracts (2026-09-27); the Kasai entries are listed by topic without numbers.
Faiss et al., 2013 (PLoS One) — "Significant molecular and systemic adaptations after repeated sprint training in hypoxia" (checked against its abstract)
n=40 trained subjects, 8 cycling repeated-sprint sessions in hypoxia (RSH, 3000 m) or normoxia (RSN, 485 m); resting muscle biopsies (mRNA) before and after; repeated-sprint-ability (RSA) test to exhaustion (10-s sprints, work:rest 1:2) with muscle perfusion by near-infrared spectroscopy.
Average sprint power in the RSA test rose to the same extent in both groups (6% vs 7%, NS); the number of sprints to exhaustion rose in RSH (9.4 ± 4.8 → 13.0 ± 6.2, p<0.01) but not in RSN (9.3 ± 4.2 → 8.9 ± 3.5).
mRNA in RSH only: HIF-1α +55%, carbonic anhydrase III +35%, MCT4 +20% (up); mitochondrial transcription factor A −40%, PGC-1α −23%, MCT1 −36% (down). Total-haemoglobin variations during sprints (perfusion) increased more in RSH.
Design: parallel groups, n=40.
Faiss et al., 2015 (Med Sci Sports Exerc) — "Repeated double-poling sprint training in hypoxia by competitive cross-country skiers" (checked against its abstract)
n=17 competitive cross-country skiers, double-blind; six sessions of 4 × 5 × 10-s sprints with 20-s recoveries, in normoxia (RSN, 300 m, n=8) or normobaric hypoxia (RSH, 3000 m, FiO2 13.8%, n=9), on a double-poling ergometer.
Peak power in the RSA test rose to the same extent in both groups (29 ± 13% vs 26 ± 18%, NS); the number of sprints completed rose in RSH (10.9 ± 5.2 → 17.1 ± 6.8, p<0.01) but not in RSN (11.6 ± 5.3 → 11.7 ± 4.3). Team-sprint average power improved 11 ± 9% (RSH) and 15 ± 7% (RSN) — no hypoxia advantage there. Upper-body (triceps) perfusion variations rose more in RSH.
Design: parallel groups, n=17.
Kasai et al., 2015 (SpringerPlus) — RSH in female athletes (not checked; no numbers kept).
Kasai et al., 2017 (Int J Sports Med) — consecutive-days RSH (not checked; no numbers kept).
Kasai et al., 2019 (J Strength Cond Res) — consecutive-days RSH block organisation (not checked; no numbers kept).
Key Results (what the two checked abstracts support)
The consistent RSH-specific effect is more sprints before exhaustion in a repeated-sprint test (cycling: 9.4 → 13.0; double poling: 10.9 → 17.1), with larger swings in muscle perfusion during sprints.
Peak or mean sprint power improved equally in hypoxia and normoxia in both studies — hypoxia did not add power, it added repeatability.
Molecular signature in cycling RSH: hypoxia-signalling and glycolytic/lactate-transport transcripts up (HIF-1α, CA III, MCT4), mitochondrial-biogenesis transcripts down (TFAM, PGC-1α, MCT1) — the opposite of an aerobic/mitochondrial adaptation.
VO2max, citrate synthase, VEGF and capillary-density changes are not reported in these abstracts; earlier versions of this entry carried percentage gains for them that could not be traced to any of the five studies.
Practical Application
In two parallel-group studies (n=40 trained cyclists; n=17 competitive XC skiers), repeated 10-s all-out sprints in hypoxia (3000 m) raised the number of sprints to exhaustion (9.4 → 13.0 and 10.9 → 17.1) while the same training in normoxia did not; peak/mean sprint power rose equally in both conditions (6-7% cycling; 26-29% double poling). RSH buys sprint repeatability, not more power and not aerobic capacity.
Requirement: a hypoxic chamber, tent or hypoxicator at ~3000 m equivalent; without it, the same sessions are ordinary repeated-sprint training, which still improved sprint power in both studies.
Not from this paper; the base's own practice: when a chamber is available the base runs RSH as a 3-4-week block, 2 sessions/week on non-consecutive days, sets of short (≤10-30 s) all-out sprints with incomplete recovery, inside a build phase, and only for events decided by repeated attacks. The number-of-sprints gains above should not be read as a promised percentage for any athlete.
Priority for long steady events stays with VO2max and threshold work (REF-081, REF-144, REF-141); sea-level alternative for sprint capacity: REF-191 (short-sprint training).
Mechanisms (from the checked abstracts)
1
Perfusion: larger total-haemoglobin swings in active muscle during sprints after RSH (both studies) — the compensatory-vasodilation hypothesis, fibre-type dependent.
2
Glycolysis / lactate transport: HIF-1α, CA III and MCT4 transcripts up after RSH (cycling study).
3
Not mitochondrial biogenesis: TFAM and PGC-1α transcripts went down after RSH in the cycling study.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from B+: composite entry without a source DOI; every number in it comes from the two checked Faiss abstracts
Content correction 2026-09-27
Faiss 2013: "n=10 athletes, 5×3 week RSH blocks; mitochondrial biogenesis, capillary density, citrate synthase up" -> abstract: n=40, 8 sessions, sprints-to-exhaustion up in RSH only, PGC-1α/TFAM/MCT1 transcripts DOWN, HIF-1α/CA III/MCT4 up.
Faiss 2015: "n=14 XC skiers, 6-week RSH" -> abstract: n=17, six sessions; sprints completed up in RSH only, peak power up equally in both groups.
Results table (peak power +5-8%, mean power +4-6%, VO2max +2-3%, citrate synthase +25-40%, VEGF +30-50%, capillary density +15-25%) deleted: untraceable to any of the five studies. Protocol (6×30 s, 13% O2, 1800-2000 m) relabelled as the base's own practice.
Level B+ -> C+ (composite without a source DOI; Kasai studies unverified); Tier "4-5 elite" -> mixed→2-3 (trained cyclists, competitive skiers).
Cross-reference labels pointed at the wrong entry or named the wrong author (checked against each cited entry's byline); repointed to the entry the label describes, or removed where the base holds no such paper.
2026-09-29: Type retyped honestly — 'research cluster of 5 studies' overstated the content: all numbers come from the two checked Faiss abstracts, the three Kasai studies carry no content. Level unchanged (C+). Candidate DOIs for the two Faiss papers (10.1371/journal.pone.0056522, 10.1249/mss.0000000000000464) await the owner's approval — found by title search, not attached.